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Earth's Earliest Gigantic and Bizarre Creatures
Much has been written about dinosaurs and the fury of T-Rex in popular culture; but are you aware there were giant creatures dominating Earth's oceans long, long before the dino-era ending 65 million years ago? Enjoy the following journey of giants and strange creatures through the time scales beginning as far back as the Cambrian Period.
The Cambrian Period began 542 million years ago (mya) and lasted till about 488 mya. Cambrian is the first period on the time scale respresenting the arrival of complex organisms.
Anomalocaris dominated the Cambrian seas for tens of millions of years. It grew to only two feet long which doesn’t seem very big by today’s standards, but in relation to anything else during the Cambrian, it was huge.
Interesting history of its stalled scientific discovery: A segment fossil of Anomalocaris, canadensis was first discovered in the Canadian Rockies in 1892, but it wasn't until 1981 that a major breakthrough about its identity occurred; and that was further refined in 1996. The one hundred year history of inaccurate theories is but one example of the difficulty identifying fossil remains of Cambrian animals having no apparent living descendants. Anomalocaris and other genera have since been discovered at various Cambrian fossil locations around the world; including the famous Burgess Shale site in Canada, Rocky Mountains in the USA, China, and Australia.
Anomalocaris with its large eyes, impaling front spines and strong swimming lobes probably could overtake any prey during its time period, including trilobites. Although, some scientists argue that its pineapple-ring mouth did not have hard parts necessary to crush the tough outer shells of trilobites. Much still remains to be clarified about their anatomy and habits. Scientists believe it swam with an "S" method of locomotion, undulating up and down the length of its body. Watch the video to observe its unique movement in the water, it actually rather mesmerizing to watch.
The second period on the time scale falls under the Ordovician Period (448 to about 443 mya).
The T-Rex of the Ordovician was a cephalopod nautiloid creature related to squids and octopuses known as the Giant Orthocone. The massive creature's living tissue was contained mostly at one end of a very long conical shell which could reach eleven meters in length. Its inner shell contained chambers that filled with water and likewise emptied in order to jet propel itself; or to descend up and down through the ocean waters. The inner chambers also contained gases for buoyancy. It seized its prey using meter long muscular tentacles and a beak-like mouth to rip them apart. It fed upon fish and large sea scorpions, its arch enemy .
Did you know fossils of Orthocones and other straight-shelled nautiloids have been quarried by Europeans for many years and adorn floors, stairs, jewelry, gravestones and art pieces with their durable and desirable beauty?
Eurypterids were sea scorpions, the largest known arthropods that ever lived. Their fossils are found all over the world. In the USA, the state of New York has unearthed an especially large number of them. Eurypterids survived a long history beginning with the Ordovician Period extending into the Permian from about 460 to 248 million years ago.That's over a 200 million year history!
Megalograptus was one of the earlier large species reaching 4 feet long, not including its front pincher claws. Most common species of eurypterids, though, were only 8 inches long. Sea scorpions walked on six legs, the back two of which were flattened like paddles. They were normally marine sea-floor dwellers, and interestingly, they could also live in freshwater. Sea scorpions preyed upon fish, trilobites and other animals living near the seabed. They had strong defenses with spines, crushing claws and armor plating. Their has been disagreement among scientists whether some of their species possessed stingers.The giant straight-shelled nautiloids were their worst enemy.
Jaekelopterus was a later species emerging during the Devonian Period around 390mya, reaching over two meters (8 feet) or more in length. Try to imagine a scorpion about the size of a kayak! Their arch enemies, the cephalopod nautiloids, declined in size during the Devonian time slot from their Ordovicain predecessors. Now the tables were turned and eurypterids like Jaekelopterus could gain the upper hand using their powerful claws to clamp down and crush the linear shells of nautiloids.
During the Devonian Period (416 till about 360mya) vertebrates had greatly arisen on the scene. A highly evolved class of fish called "placoderms", possessing advanced characteristics stemming from their predecessor "ostracoderms", dominated the ancient seas. For protection, both classes of fish possessed armored plates covering their head and upper torso regions. They looked very unusual compared to modern fish species. The main advancement with placoderms was the development of a jawbone and paired fins. Those two significant adaptations provided them the necessary speed and power to become fearsome predators, aggressively chasing prey rather than waiting for the perfect opportunity. Ostracoderms were eventually overrun into extinction unable to compete with their cousin placoderms.
The Dunkleosteus placoderm was the T-Rex of the Devonian terrorizing the ancient seas. He measured 10 meters (33 feet) and weighed almost 4 tons. Instead of teeth, Dunkleosteus possessed two pairs of impaling sharp boney blades. Dunkleosteus could open its mouth in 1/50th of a second, which would have caused a powerful suction that pulled the prey into its mouth, a food-capturing ability reinvented by many of the most advanced fishes today. Then it could bite down with a pressure of up to 8,000 pounds per square inch (55mph), placing it in the league of T-Rex and modern crocodiles! There wasn’t anything the great placoderm didn’t or couldn’t eat, including its own kind.
In recent decades, Dunkleosteus has finally achieved the recognition it deserves as a super predator. There are a large number of its fossil specimens on display which have been found in North America, Poland, Belgium and Morocco.
Terataspis, grandis whose name means “great monster shield” was a large spiny trilobite. Trilobites had to evolve some serious defenses to survive predators of the Devonian. Like most trilobites,Terataspis, grandis was a bottom feeder, scavenging anything it could find, but it also was an opportunistic predator preying on burrowing animals such as mollusks, worms and smaller arthropods. It reached about two feet in length which in relation to most trilobites was enormous. Having the distinction of a segmented body, multiple jointed limbs and an armored outer shell, places it in the category of arthropods related to insects and crustaceans.
Going back in the time scale, the largest trilobite ever found is Isotelus, rex from the Ordovician Period. It reached 28 inches in length. Many of Isotelus, rex fossils have been discovered in the great state of Ohio where it is the proud state fossil.
Beginning in the late Devonian Period and into the early Carboniferous Period (360 to 300mya) sharks were diversifying so much that scientists have labeled it the “Golden Age of Sharks”. The placoderms were dying out, only lasting a 50 million year history compared to sharks 400 million year history. With the decline of placoderms, environmental niches allowed sharks to fill in and as a result they assumed a wide variety of bizarre shapes. From this stage of evolution they had become the top predators of the oceans.
Stethacanthus grew 11 feet long (sources differ). One thing undisputed is the strange anvil growth protruding from its back. This was completely topped with sharp spikes which also covered the top of its head. There’s much speculation about its use, one theory proposes it may have played a role in courtship. Or, it may have just made the creature look more frightening.
Another strange shark emerging during the period was Helicoprion. Not much is truly known about this shark, but the pattern of its teeth is instantly recognizable. They formed a whorl semi-circle arrangement protruding out of its mouth. Unlike modern sharks,the teeth did not fall away at the front resulting in the rotated bizarre spiral which mystifies modern science.
The largest genus of sharks in the bizarre top predator category was Edestus, giganteus which lived during the latter part of the Carboniferous. He probably grew 20 feet long weighing in up to 2 tons. That's comparable to the great white shark today of which the largest can reach that long, but the average is about 15 feet long. Like its relative Helicoprion, Edestus, giganteus's teeth formed a strange curved shape, and it also did not shed its teeth. It must have been very intimidating to other creatures looking as if it possessed saw blades for a mouth.
Ammonites were closely related to the straight-shelled cephalopod nautiloids. Their main difference would be the coiling of the shell which allowed them more freedom of mobility. They even used the same jet propulsion mode of movement. Their numbers greatly grew, beginning as early as the Devonian and peaking some 300 million years later during the Cretaceous Period (145 - 65 mya). Consecutively, the straight-shell forms greatly declined, unable to compete with the more mobile ammonite nautiloids. The ammonites were so successful and numerous that their remains are now excellent index fossils for scientists to date rock layers. The biggest forms are found in later rocks of the upper Jurassic Period (200mya-145mya) such as Titanites, sp. Another huge form, Parquzosia, seppenradesis from the Cretaceous Period, was found in Germany reaching 2 meters (6.5 foot diameter).
The ammonite shown with the lady was discovered 60 years ago on the side of a mountain in British Columbia. It is not yet scientifically recognized until it can be collected and turned over to an authoritative institution. It is assumed to be a Titanites and is being evaluated by a company to collect it. The fossil measures 2 meters (6.7 foot diameter).
The super successful ammonites experienced the same fate 65 million years ago along with the dinosaurs. The nautilus, their close relative often referred to as a living fossil, is the lone survivor of nautiloids.
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Learn more interesting facts about Paleozoic Fossils. There, I have included more fossil discoveries, drawings, photos and fossil classifications.